U. S. Standard Sieve Series

Bureau of Standards Sieve Number	Specified Sieve Opening		Specified Wire Diameter Inches	Tolerances Permitted
	Inches	Microns		Average Opening	Wire Diameter	Maximum Opening
4	.187	4760	.050	+ - 3%	- 15% to + 30%	10%
5	.157	4000	.044	+ - 3%	- 15% to + 30%	10%
6	.132	3360	.040	+ - 3%	- 15% to + 30%	10%
7	.111	2830	.036	+ - 3%	- 15% to + 30%	10%
8	.0937	2380	.0331	+ - 3%	- 15% to + 30%	10%
10	.0787	2000	.0299	+ - 3%	- 15% to + 30%	10%
12	.0661	1680	.0272	+ - 3%	- 15% to + 30%	10%
14	.0555	1410	.0240	+ - 3%	- 15% to + 30%	10%
16	.0469	1190	.0213	+ - 3%	- 15% to + 30%	10%
18	.0394	1000	.0189	+ - 3%	- 15% to + 30%	10%
20	.0331	840	.0165	+ - 5%	- 15% to + 30%	25%
25	.0280	710	.0146	+ - 5%	- 15% to + 30%	25%
30	.0232	590	.0130	+ - 5%	- 15% to + 30%	25%
35	.0197	500	.0114	+ - 5%	- 15% to + 30%	25%
40	.0165	420	.0098	+ - 5%	- 15% to + 30%	25%
45	.0138	350	.0087	+ - 5%	- 15% to + 30%	25%
50	.0117	297	.0074	+ - 6%	- 15% to + 35%	40%
60	.0098	250	.0064	+ - 6%	- 15% to + 35%	40%
70	.0083	210	.0055	+ - 6%	- 15% to + 35%	40%
80	.0070	177	.0047	+ - 6%	- 15% to + 35%	40%
100	.0059	149	.0040	+ - 6%	- 15% to + 35%	40%
120	.0049	125	.0034	+ - 6%	- 15% to + 35%	40%
140	.0041	105	.0029	+ - 8%	- 15% to + 35%	60%
170	.0035	88	.0025	+ - 8%	- 15% to + 35%	60%
200	.0029	74	.0021	+ - 8%	- 15% to + 35%	60%
230	.0024	63	.0018	+ - 8%	- 15% to + 35%	90%
270	.0021	53	.0016	+ - 8%	- 15% to + 35%	90%
325	.0017	44	.0014	+ - 8%	- 15% to + 35%	90%